1. Field of the Invention
The present invention relates to a spool retainer that prevents the two spools of a tape cartridge from unwinding during shipping or storage and also serves as an installation aid that remains on the cartridge during installation into a device such as a printing mechanism to retain and precisely locate the ribbon within the mechanism during installation.
2. Description of Related Art
In one type of thermal printing device, a thermal printhead presses a donor film ribbon, housed in a ribbon cartridge, onto the surface of a copy sheet. Such a device requires frequent replacement of the ribbon cartridge. The cartridge has an exposed ribbon surface that requires protection during storage prior to use to protect the ribbon and to prevent ink on the ribbon from contaminating the surroundings.
An additional problem associated with cartridges, and especially ribbon cartridges for small sized printers, is that there is usually only a very narrow space between a printhead and an opposing platen through which the exposed portion of the ribbon must pass when being installed on the printing device. Often, there is difficulty in installing such a cartridge even to a skilled user. Further, there is a need to protect and precisely locate and retain the exposed portion of ribbon during storage and during installation of the cartridge onto the printing device.
There are several known devices that provide a storage case or packaging for cartridges or cassettes that house spools of ribbon or magnetic media. Examples of these devices are described in U.S. Pat. No. 3,381,810 to Lasher et al., U.S. Pat. No. 4,119,200 to Cassidy et al., U.S. Pat. No. 3,272,325 to Schoenmakers, U.S. Pat. No. 4,140,219 to Somers, and U.S. Pat. No. 3,380,581 to Landgraf.
Known storage cases address the need to protect the cartridge during storage, but fail to appreciate the need to protect and retain the cartridge during installation. All of the identified prior art patents teach and require removal of the cassette or cartridge from its storage case prior to installation into a printing device. As such, they fail to protect and retain the cartridge at the crucial time immediately prior to and during installation.